Sports & Gaming · Statistics · Descriptive Statistics
Effective Field Goal Percentage Calculator
Calculate Effective Field Goal Percentage (eFG%), which adjusts a player's shooting percentage to account for the extra value of three-point field goals.
Calculator
Formula
FGM = total field goals made (including 3-pointers); 3PM = three-point field goals made; FGA = total field goal attempts. The 0.5 multiplier on 3PM reflects the extra half-point of value a made three-pointer provides compared to a two-pointer, on a per-attempt basis.
Source: Basketball-Reference.com Glossary; Oliver, Dean — 'Basketball on Paper', 2004.
How it works
The formula is eFG% = (FGM + 0.5 × 3PM) / FGA. Because a three-point field goal is worth 50% more points than a two-point field goal, each made three-pointer is credited as 1.5 field goals rather than 1 when measuring efficiency. Dividing this adjusted total by total field goal attempts gives a per-attempt efficiency measure on the same 0–1 (or 0–100%) scale as traditional FG%.
Traditional FG% treats every made basket equally, regardless of its point value. This creates a misleading picture when comparing a center who scores almost exclusively on high-percentage two-point shots near the basket versus a guard who takes many three-pointers. A guard making 40% of three-pointers (1.2 points per attempt) is actually more efficient than a center making 48% of two-pointers (0.96 points per attempt), yet traditional FG% would show the center as more efficient. eFG% corrects this distortion.
eFG% is one of the 'Four Factors' identified by Dean Oliver as a key determinant of team success in basketball. It is used by all 30 NBA teams in player evaluation, in sports broadcasting, and as a cornerstone metric on sites like Basketball-Reference.com. A league-average eFG% in the NBA is typically around 53–55%, while elite shooters can exceed 60%.
Worked example
Example: Stephen Curry — Hypothetical Season
Suppose a player records: FGM = 450, 3PM = 150, FGA = 1,000.
Step 1 — Traditional FG%: FG% = 450 / 1,000 = 0.450 = 45.0%
Step 2 — Apply the eFG% formula: eFG% = (450 + 0.5 × 150) / 1,000 = (450 + 75) / 1,000 = 525 / 1,000 = 0.525 = 52.5%
Step 3 — Interpret the difference: The eFG% of 52.5% is 7.5 percentage points higher than the traditional FG% of 45.0%, entirely because of the player's high three-point volume. This player is producing 1.05 points per field goal attempt (525 points / 500 two-point equivalent makes), which is well above average.
Step 4 — Three-Point Rate: 3PM / FGM = 150 / 450 = 33.3% of all made baskets were three-pointers, driving the eFG% boost.
Limitations & notes
eFG% does not account for free throws, which are also a highly efficient scoring method. The related metric True Shooting Percentage (TS%) extends eFG% by incorporating free throw attempts and free throws made, giving a more complete picture of overall scoring efficiency. eFG% also does not reflect shot difficulty, assist-to-turnover context, or whether attempts were contested or open. Additionally, small sample sizes (e.g., a player who has taken only 10 shots) make eFG% unstable and unreliable as a performance indicator — typically at least 200–300 attempts are needed for the metric to stabilize. eFG% cannot exceed 100% mathematically (since FGM + 0.5×3PM ≤ 1.5×FGA at most), but inputs where 3PM exceeds FGM are logically invalid and will return an error.
Frequently asked questions
What is the difference between eFG% and traditional FG%?
Traditional FG% divides all made field goals by all attempts, treating two-pointers and three-pointers as equal. eFG% multiplies made three-pointers by 1.5 before dividing by attempts, giving credit for the extra point value of a three-point make. A player who hits 40% of three-pointers has a higher eFG% than a player who hits 40% of two-pointers, correctly reflecting the three-point shooter's greater scoring output per attempt.
What is a good eFG% in the NBA?
The NBA league average eFG% typically falls between 53% and 56% depending on the season. Individual values above 58% are considered excellent, and values above 62% are elite. For reference, league-wide leaders often post eFG% above 65% in a season. Below 50% is generally poor, though context matters — a center finishing around the rim at 50% eFG% may still be valuable due to high-percentage shot selection and drawing fouls.
Why does eFG% multiply three-pointers made by 0.5 instead of 1.5?
The formula credits each three-pointer with an extra 0.5 (i.e., FGM already counts the three-pointer once, so we add 0.5 more to represent the 50% extra value). This is mathematically equivalent to weighting three-pointers at 1.5 and two-pointers at 1.0. Both approaches yield the same result — the 0.5 formulation is simply a convenient shorthand that adds the incremental value on top of the existing FGM count.
Can eFG% be used for teams as well as individual players?
Yes. eFG% is routinely computed for entire teams using their collective FGM, 3PM, and FGA totals. Team eFG% is one of Dean Oliver's 'Four Factors' of basketball success and has been shown to have the strongest correlation with winning of the four factors. Comparing offensive eFG% to defensive eFG% allowed reveals a team's net shooting efficiency advantage.
What is True Shooting Percentage and how does it differ from eFG%?
True Shooting Percentage (TS%) extends eFG% by also accounting for free throw scoring. The formula is TS% = Points / (2 × (FGA + 0.44 × FTA)), where FTA is free throw attempts. eFG% ignores free throws entirely, so a player who draws many fouls will have their full scoring efficiency underrepresented by eFG%. TS% is generally considered a more complete measure of scoring efficiency, while eFG% is simpler and more directly comparable to traditional FG%.
How many shot attempts are needed for eFG% to be reliable?
Statistical reliability generally requires at least 200–300 field goal attempts for eFG% to stabilize meaningfully. In small samples (fewer than 50 attempts), random variation can make a player's eFG% look dramatically better or worse than their true ability. For game-to-game analysis, eFG% is highly volatile; for season-long analysis, it becomes a robust indicator. Always consider sample size when interpreting eFG% for role players or mid-season statistics.
Last updated: 2025-01-30 · Formula verified against primary sources.